DRV8323: Problem with DRV8323's status information at the moment the DRV8323 is about to turn off.

Banghyun Cho

Part Number: DRV8323

Hi experts

I am controlling the motor with DRV8323. The status information of the DRV8323 is being read continuously by SPI communication. The moment the power is about to turn off, the status information from the DRV8323 sends all values in the status register as having an error. I'm curious what happens to the DRV8323 when it powers down and if there's a way to fix this.

Thank you!

over 2 years ago

0 Anthony Lodi over 2 years ago

TI__Mastermind 18490 points

Hi Banghyun,

Thank you for your question! What is the VM voltage of the DRV when you start noticing this behavior as the device is shutting down? You may need to probe the VM voltage while showing the SDO output to determine this.

Anthony Lodi

0 Banghyun Cho over 2 years ago in reply to Anthony Lodi

Prodigy 20 points

If the VM is 24V and DRV8323 is disabled before the power is turned off, can all status information of DRV8323 send an error while DRV8323 is disabled?

+1 Anthony Lodi over 2 years ago in reply to Banghyun Cho

TI__Mastermind 18490 points

Hi Banghyun,

When the enable pin is low, the SPI bus is disabled (see section 8.4.1.1 "Sleep Mode" in the datasheet). If you are tying the external pullup on the SDO pin to an external 3.3V supply, and if you attempt to send a read command over SPI while the enable pin is low, since the SPI bus is disabled the SDO pin will remain pulled up to 3.3V which will give the appearance that the SDO Pin is returning all 1s. When the enable pin is pulled low to put the device in sleep mode then the MCU needs to recognize that the SPI bus data is no longer valid.

Regards,

Anthony Lodi

Motor drivers

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DRV8323: Problem with DRV8323's status information at the moment the DRV8323 is about to turn off.